Abbey of Fontevraud
Fontevraud Abbey was founded by Robert d'Arbrissel in 1099, and soon spawned a few dozen daughter houses in France, Spain and England. The first permanent structures were built between 1110 and 1119. Within its walls were both a nunnery and a monastery, but its head and senior "officers" had to be women. This was possibly because the nuns' contingent included some formidable female talent in the form of royalty and nobility - and a few discarded royal mistresses.
After the death of Richard I in 1199, Eleanor of Aquitaine retired to Fontevraud and was buried there alongside her husband (Henry II) and son (Richard I). The Abbey became the burial place a number of other Plantagenets; at one stage containing 15 of their tombs (though no more kings). Just four are still identifiably there today - Henry II, Eleanor, Richard I and Isabella (John's Queen - his tomb and effigy are in Worcester Cathedral, though his heart was buried somewhere at Fontevraud).